1. Field of the Invention
The present invention relates to a pair of pliers, and more particularly to a pair of pliers for operating a workpiece, such as a pipe, rod and the like.
2. Description of the Related Art
A pair of conventional pliers comprise an elongated shank, a fixed jaw locked onto at least one end of the shank, and a movable jaw pivotally mounted on the at least one end of the shank and movable relative to the fixed jaw. The fixed jaw has a surface provided with a plurality of locking teeth. The movable jaw has a surface provided with a first toothed face and a second toothed face. The first toothed face of the movable jaw is provided with a plurality of first engaging teeth. The second toothed face of the movable jaw is provided with a plurality of second engaging teeth. Thus, a workpiece is clamped between the locking teeth of the fixed jaw, the first engaging teeth of the first toothed face of the movable jaw and the second engaging teeth of the second toothed face of the movable jaw. In such a manner, the movable jaw is movable relative to the fixed jaw to clamp workpieces of different sizes by a pivot action of the movable jaw. However, when the swinging angle of the movable jaw exceeds a determined value, the locking teeth of the fixed jaw, the first engaging teeth of the first toothed face of the movable jaw and the second engaging teeth of the second toothed face of the movable jaw cannot engage the surface of the workpiece efficiently, so that the workpiece easily slips from the fixed jaw and the movable jaw of the pliers, thereby causing inconvenience to the user.
The closest prior art references of which the applicant is aware are disclosed in U.S. Pat. Nos. 2,559,973; 6,026,714; 6,742,419; 7,044,030 and 7,096,764.